Slide core tuning device



Nov. 29, 1949 T. A. SPOOR 2,489,595

SLIDE GORE TUNING DEVICE Filed April 25, 1946 I THEODOJPUS A. SPOOR 46 5 INVENTOR.

1 n t W ATTORW Patented Nov. 29, 1949 suns com: TUNING nsvics Theodor-us Antonius Spoor. Eindhorven, Netherlands. asslgnor, by mesne assignments, to Hartford National Bank and Trust Com ford, 00m, as trustee panyJlart- Application April 23, 1948, Serial No. 684,401 In the Netherlands April 4, 1942 Section 1, Public Law 890.

A4ugust 8, 1948 Patent expires April 1962 4 Claims. (CL Ill-242) This invention relates to a slide core tuning device 1. e. a tuning device whose adjustment to various frequencies or a. certain range or frequencies is effected by engaging a core consisting of so-called high-frequency iron which extends to a greater or lesser extent into the space surrotmded by the winding of the coil and more particularly to,a device of this kind in which the driving member for moving the slide core engages the core at the height of a part of the core itself.

In devices of this kind, which are constructed in a known manner, the total length is much greater than the length of a coil having a stationary iron core, due to the space which must remain available for moving out the core.

shielding means thereof, the driving device for the slide core and the terminals, the height of the foot being matched to the length of the slide core.

In this way it is ensured that the space required at any rate for leading the coil connections through the foot of the coil and for the customary soldering tags is also utilized for providing the space for the core in the movedout position. In a suitable form oi. construction a hollow column is positioned on the base of the foot, which column supports the coil former and in which moves the slide core. Moreover, the shaft of a pinion is joumalled in the column in the vicinity of the end of the coil, which pinion meshes with a gearing provided on the core. The advantage of this construction consists in a very stable assembly of driving means and bearings of the slide core associated with a compact mounting.

It is known per se to readjust the inductance of an iron core coll by shifting the iron core which is provided with teeth engaging the teeth of the pinion which can be rotated form-adjusting the inductance.

When making use of the present invention preferably one of the bearings of the pinion is given a conical shape and placed in the immediate proximity of the pinion, thus avoiding beforehand play in the bearing.

2 have been arranged about the coil a correction of the position of the iron core relatively to the coil is still possible. In order that with constructions according to the invention, in which no elongation of the core projects from the shielding means. such adjustment may be possible after the shie ding means have been provided the shieldin! box is, according to the invention, provided with an aperture through which the pinion can be mounted and driven. the shielding means extending to the base of the foot. and the part of the shaft of the pinion co-operating with the conical bearing being caused to engage this bearing by a plate spring which can be in roduced from the bottom side of the foot. In this way the pinion can still be adjusted relatively to the iron core after mounting the shielding means.

In a suitable form of construction of a device according to the invention the hollow column extends through the base oi. the foot or the coil beyond the bottom thereof at which he ht are provided also the coil connections. Thus the available space in the coil construction is utilized as much as possible.

Accordin to the invention, in order to secure a suitable guiding of the iron core and a driving without back lash the end of the core first entering the coil case is preferably led through the interior of the coil cam at the same side of the core where the driving member is provided and is caused to engage the said guiding and the driv- In other well-known constructions of such slide a core tuning devices the core is driven by means 0! n 6345118101150 that after the shielding means 56 being an elevation of the driving pinion and l'iging member by a spring member provided at the other side 01' the core between the driving device and the said end.

The spring member may be constituted with advantage by a pressure roller which by means of a spring provided adiacent the column is caused to engage the core through a slit in the column. This form of construction also contributes to the obtalnment of a very compact assembly.

According to the invention. for exactly adjusts ing the position of the coil relatively to the iron core use may be made with success of the construction in which the coil case. at the side where it is not supported by the foot, is so secured to the top of the shielding means as to be adjustable in a longitudinal direction.

The invention will be more fully explained by reference to the accompanying drawing, in which Figures 1 and 2 represent partly in elevation, partly in section the foot of a slide core tuning device according to the invention in two direcflOIiB. '1

Figure 3 is a plan view of the foot, Figure 4 illustratingtheattachmentofthecoilcase shielding shows a coil former I about which are I. This coil former is supbythc foot ll of the coil which also carshielding box "and the driving device hich will be described more in detail hereinafter. order that the inductance of the turns I may adjusted the coil former i contains a core I! high-frequency iron which can be moved to therein. The driving of this slide core h eifected by providing the-core with a rack ll engaged by the teeth of a pinion It.

The pinion it is provided at the side of the coil ere the core enters the coil.

On the baseof the foot is positioned a hollow.

column I! which constitutes the support proper of the coil case and within which moves the slide core, this column containing at the same time the bearings for the shaft of the pinion It. The column extends through the base ll of the foot ll of the coil beyond the bottom of the foot at which height are also provided the terminals II of the coil.

In order to support the coil former I the column I! is provided with a vertical cylindrical aperture l4 exactly engaged byv the coil former I. The slide core II, which has a circular cross-section, is provided at the top with a guide cam is which passes over the inner wall of the coil former. The teeth of the slide'core are caused to engage the teeth of the pinion 36 by means of a pressure roller H and a spring it, for which purpose a slit n is provided in the column, the mounting being such that the pressure roller I1 is provided at the side of the slide core remote from the pinion II and the cam i8 and is caused to engage the core between these two parts. By the action of the pressure roller and the spring the teeth of the core are caused to engage those of the pinion it on the one hand, whereas on the other hand the cam is steadily remains in mechanical contact with the inner wall of the coil former I. In this way it is ensured that no play can occur in the driving between the pinion and the gearing of the core. In order that the pinion SI itself may also be so journalled as to be free from play use is made of the construction shown in Figures 2 and 4, in which the pinion in the immediate vicinity of the gearing is furnished with a conical part which cooperates with a conical gearing 43, the pinion being steadily caused to engage this conical bearing by a spring 2!.

As a rule it is desirable that the position of the iron core should be adjustable relatively to the turns after the shielding box has been placed over the coil. Since in the construction according to the invention the iron core is not accessible from the exterior the following construction is proposed. The shielding box is provided with an aperture through which the pinion can be mounted and driven. and the plate spring 22 having to press the part of the pinion shaft cooperating with the conical bearing against the latter can be introduced from the bottom side through the foot so that the pinion can be provided after the shielding means have been mounted.

As appears from Figure 3 this yields the advantage at the same time that the diameter of the shielding box can be made smaller than in the case of a construction in which the pinion is moimted before the shielding box.

In Figure 3 a portion of the pinion shaft extends through the shielding means, which is not bore 21 and at one side with a cam 20 so thatthe pinion can be driven by means of a shaft which may be led through the bore 21. This shaft may have secured to it a carrier which cooperates with a cam 28 for rotation of the pinion. When it is desired simultaneously to drive a pinrality ,of tuning devices according to the invention the latter are arranged one behind the other in such mannerthat the bores 21 of the various pinions lie as exactly as possible in a straight line, whereupon a thin shaft is successively passed through the various pinions which shaft is provided at the required points with carriers co-operating with the cams v26.

Figure 5 represents schematically how the side of the coil case I. which is not supported by the foot, is secured to the top l5 of the shielding box in such manner that the coil case can be shifted in a longitudinal direction. To this end the coil case is provided at the top with a flange 4' and a threaded portion 41 engaging an aperture provided therefor in the upper wall 45. Between the flange 48 and the inner side of the wall It is provided a slightly curved spring ll which tends to lower the coil case. By turning a nut 49 fitting on the screw thread 41 the distance of the top of the coil to the upper wall of the shielding means and consequently the position of the coil relatively to the iron core can be ad- Justed. Furthermore the coil body comprises at its top a hexagonal portion 50. The aperture made in the upper wall is also hexagonal, thus preventing the coil from following the nut 49 on screwing down the latter.

I claim:

1. A slideable core inductance unit, comprising a supporting base provided with a tubular projection, a hollow columnon the base having an aperture in the wall thereof, a tubular coil supporting member supported by the column, a coil wound on the coil supporting member, a

which member enclosing the coil and supported by the base, a toothed core slideable within said coil supporting member, a pinion gear for engaging the teeth on the core for moving the core into and out of the coil, the core in the out osition being partially housed in the tubular extension of the base, a conical bearing operatively associated with the pinion gear, and a shaft extending through the aperture in the wall of the column and journalled in the conical bearing for controlling movement of the bearing.

2. A slideable core inductance device as claimed in claim 1, in which a spring is provided for axially urging the conical bearing to engage the pinion.

3. A slideable core inductance device as claimed in claim 1, in which the hollow column extends through the base and forms the tubular projection thereof and connecting terminals are provided on the base for the coil.

- 4. A slideable core inductance device, comprising a supporting base, a hollow column extending through the base having an aperture in the wall portion above the base, a tubular coil supporting member supported by the column above the base, a coil wound on the coil supporting member, a shield member enclosin the coil and supported on the base, a core slideable within the coil supporting member having a plurality of gear teeth on one side thereof and a substantially free surface on the other side thereof, a pressure roller engaging the free surface of the core for applying pressure between the core and the coil supporting member, and gear means en- 5 gaging the gear teeth on the core between the ends thereof for moving the core into and out 0! the coil supporting member, the core in the out position being partially housed in the extenaion of the column beneath the supporting base.

THEODORUS ANTONIUS SPOOR.

REFERENCES CITED The following references are of record in the file of this patent:

8 UNITED STATES m'mn'rs 

